Question

A train running at a speed of $45km$ per hour is $400m$ long . How long will it take to pass a vendor standing on the station platform ?

Answer 1

To pass a vendor standing on the platform the train must travel $400m$.
Since, Speed$=\frac{\text{Distance}}{\text{Time}}$
$\Rightarrow$Time$=\frac{\text{Distance}}{\text{Speed}}$.....(i)
Given speed $=45km/hr=\frac{45000m}{3660sec}=12.5m/sec$
Thus, the train travels $12.5m$ in $1$ sec
Therefore, time required to travel $400m$ $=\frac{400}{12.5}$ [From equation(i)]
$=32$ sec.
Hence, the required time to pass a vendor standing on the station platform$=32$ sec.